1. Field of the Invention
The present invention is directed towards submunitions and grenades and, more particularly, to an environmental charging and detonation device for a submunition that provides more reliable performance and greater safety related thereto than conventional mechanically activated devices.
2. Description of the Prior Art
Many of the submunitions and grenades now in use require a mechanical firing pin to impact a stab detonator in order to detonate the explosives found in these devices. It has been demonstrated that a firing system relying on a firing pin to strike a stab detonator is not sensitive to impact angles significantly less than 90.degree. with respect to a ground target. Consequently, the battlefield becomes contaminated with armed submunitions that can be triggered upon contact by vehicle or personnel walking though the battlefield.
An example of a present mechanical submunition firing system is exhibited in the Army's M223 fuze. This fuse is used in the Army's M42/M46 submunition grenades which are stacked one into the other and carried either by artillery projectile or rocket cargo rounds. At some height above a target the cargo round is blown open by a separate fuze and the arrays of submunitions from the projectile are dispersed to form an umbrella pattern. Each submunition contains its own M223 fuze which is armed on its way to the target. The stab firing pin in the M223 fuze is threaded along part of its length for securing it to the submunition housing in a safe position prior to arming. The firing pin is also used to secure a spring loaded slider containing a stab detonator. When the submunition is released from the cargo round a ribbon is deployed that unscrews the stab firing pin. This action releases the spring loaded slider, containing the stab detonator, causing the detonator to snap into alignment with the stab firing pin. The stab firing pin then functions the submunition, by striking the stab detonator, upon impact by the submunition with the ground or target. However, the required striking action by the firing pin in this fuze is very unreliable. Impact by the submunition must be very close to vertical with respect to the ground and with sufficient force in order for it to operate properly. Additionally, the ribbon deployed to unscrew the firing pin is unreliable. For slow or nonspinning rounds, such as exhibited by rockets, the ribbon does not generate enough spin on its own to unscrew the firing pin. Consequently, not only are current mechanical submunitions insensitive to oblique angles of impact they are also unreliably armed.